Piston



June 9, 1936. D. J. CAMPBELL PISTON Original Filed Feb. 15, 1933 3 Sheets-Sheet l June 9, 1936. D. J. CAMPBELL PISTON 5 Sheets Sheet 5 Original Filed Feb. 13, 1935 1701151101 J: Cm nhb 2Z1 (loam S Patented June 9, 1936 PATENT OFFICE PISTON Donald J. Campbell,

Ottawa County,

Spring Lake Township, Mich., assignor to Campbell,

Wyant and Cannon Foundry Company, Norton Township, Mich., a corporation of Michigan Application February 13, 1933, Serial No. 656,399 Renewed November 29, 1935 5 Claims.

The present invention relates to pistons for engine cylinders, particularly of the internal combustion type and more particularly of the Diesel type; and its object is to provide such a piston having improved means for preventing fluid leakage past the piston, especially in cylinders having great fluid pressure therein.

This and any other and more specific objects hereinafter appearing are attained by, and the invention finds preferable embodiment in, the illustrative piston structure particularly described in the body of this specification and illustrated by the accompanying drawings, in which:

Figure 1 is an elevational side view of of an engine;

Figure 2 is an upper end view thereof;

Figure 3 is an axially sectionalview of the same;

Figure 4 is a transaxially sectional view of portions thereof taken on line 44 of Figure 3;

Figure 5 is an elevational side view ,of athreada piston ed ring part of the same;

Figure 10 is an elevational side view of a helical sealing element comprising mutually contacting members;

Figure 11 is an upper end view thereof.

In the embodiment of the invention illustrated by these drawings, a reciprocating piston for an engine cylinder is shown having the hollow cylindrical body or body member I provided with the usual bearing 2 for the wrist pin of the piston rod, the closed upper end 3 having angularly spaced strengthening ribs 4, etc. This body I has an annular recess internally conical, or bevelled inwardly-downwardly in said bodys radial directions, as particularly shown in Figure 3. An annular member 6 surrounding the body member has an annular lower end I coni-' 1y contracted by the engaging of its conical lower end I with the correspondingly formed recess 5; and that it expands when moved upwardly.

A ring 9 is threaded at I 0 'on'the piston body Figure 6 is a lower end view of a portion therc and is turnable therearound to the position seen a in Figure 3 wherein its inwardly extending flange ll tightly contacts the piston body at l2 in fluid sealing relation This ring 9 has a lower end or annular shoulder designated generally I3, and the piston body I is provided with an annular shoulder designated generally M, said shoulder with which the piston body is thus provided being the upper edge of annular member 6. A sealing element, designated generally 15, surrounds the piston body between said shoulders l3 and M and is held thereby against movement axially of the piston.

This element l5 which sealingly contacts in inner surface of the engine cylinder to prevent fluid leakage past the piston, is shown of helical form, :and as comprising a plurality of helical members, three such members IS, IT, I8 being shown in Figures 1, 3 and 10. These members helically engage each other being turned between and on each other to form the complete sealing element l5 as seen in Figure 10. The said element l5 engages at its upper end the correspondingly helically formed shoulder l3 of ring 9 and at its lower end engages the correspondingly helically formed shoulder I l of the annular member 6. These shoulders comprise helical portions [9, 20, 2| on the ring 9 and 22, 23, 24 on the annular member 6, said portions being angularly spacedand being stepped apart to provide stops 25, 26, 21 on the ring and 28, 29, 30 on the an nular member.

The upper ends 3|, 32, 33 of the members of the helical sealing element abut on the respective stops of ring 9 and their lower ends 34, 35, 3B abut. on the stops respectively of the annular member 6 respectively, which operates as a ten-,,

better distributing the oil around the cylinders inner surface. This action also tends to prevent scoring of the cylinder.

The annular, sealing element is shown provided with a longitudinal channel 31 filled with a solid lubricant 38, like.

As the ring 9 is screwed down, the members l6,

as graphite composition or thel1, 18 of the helical sealing element I5 are pressed into sealing contact with each other and with the shoulders l3, I4, and as the pressure of the ring increases on said element the annular member 6 is forced down farther into the recess 5, being diametrically contracted in such movement; and as the ring 9 is turned reversely, the annular member 6 is permitted to expand by its resiliency.

It is contemplated that the ring 9, when turned to properly adjusted position, may be fixed therein as by the set screw 39 threaded in said ring and seating in a socket 40 in the upper end of the piston body. In such adjusted position, any expansion or contraction of the piston body in its axial direction caused by the heating or cooling thereof or by the heating or cooling of one part or one end thereof more rapidly than the heating or cooling of other parts or the other end of the piston body, will not seriously affect said elements scaling function. Nor will the heating or cooling of other parts seriously affect such function. As this helical sealing element l5 heats it expands lengthwise, i. e. in its helical direction thus turning by said stops the annular member 6, against friction, in the recess 5, and said member is also pressed downwardly in the recess 5 and thus contracted; but as the sealing element l5 cools and contracts, the said annular member expands by its resiliency and rises. The provision of a plurality of members of the sealing element l5, with their ends angularly spaced equally apart, renders the action of said element more uniform around the piston and cylinder. The heating and cooling of the parts compensate or offset each other, for as the piston body expands by heating, the space between said shoulders increases and the sealing element [5 (including its members) also expands lengthwise thus taking up such increased distance between the shoulders, and the annular member 6 also expands and moves upwardly.

The invention being intended to be pointed out in the claims, is not to be limited to or by details of construction of any particular embodiment thereof illustrated by the drawings or hereinbefore described.

I claim:

1. An engine piston comprising: a body provided with a shoulder comprising helical portions stepped to provide stops therebetween; a ring threaded on the body provided with an annular shoulder comprising helical portions stepped to provide stops therebetween; a helical sealing element surrounding the body between the shoulders comprising helically engaging members having ends abutting a stop of the body portion and a stop of the ring respectively, and being pressed into sealing relation with each other, with the shoulders and with the cylinder.

2. An engine piston comprising: a body provided with a shoulder comprising helical portions equally angularly spaced and stepped toprovide stops therebetween; a ring threaded on the body provided with a shoulder comprising helical portions equally angularly spaced and stepped to provide stops therebetween; a helical sealing element surrounding the body between the shoulders comprising helically engaging members having ends abutting a stop of the body portion and a stop of the ring respectively, and being pressed into sealing relation with each other, with the shoulders and with the cylinder.

3. An engine piston comprising: a body member; a compressible-expansible annular member surrounding the body member and having a he1i-' cal portionand a stop, one of said members having a conically formed annular end portion and the other one of said members having a correspondingly formed annular recess receiving said end portion; a helical sealing element surrounding the body member; an element having a helical portion and a stop, and secured to said body member in sealing relation therewith; said helical sealing element being in sealing relation with said helical portions and stops.

4. A piston for engines comprising a piston body provided with an annular shoulder at the head end thereof and a threaded portion adjacent said shoulder and an annular conical shoulder axially spaced from said threaded portion; an

annular ring embracing the said threaded por- 3 tion, the said annular ring being provided with transverse abutment shoulders a split ring positioned against the annular conical shoulder provided with transverse abutment shoulders; and a plurality of helical sealing elements surrounding the piston body between the aforesaid annular and split rings and supported in sealing position thereby by the axial shoulders thereof.

5. A piston for engines comprising a piston body; an annular ring shouldered on the body and threaded thereto, the said ring being provided with a plurality of axially spaced shoulders; a split ring shouldered on the piston body and spaced from the annular ring, the said split ring being provided with a plurality of transverse shoulders; and a plurality of helical packing rings supported in flexible sealing relation against the cylinder wall by the transverse shoulders of the said annular ring and of the split ring.

DONALD J. CAMPBELL. 

